updated from Atlas

Author: ramalho

18-with-match/lispy/py3.10/examples_test.py

@@ -2,16 +2,12 @@
 Doctests for `parse`
 --------------------
 
-# tag::PARSE_ATOM[]
+# tag::PARSE[]
 >>> from lis import parse
 >>> parse('1.5')
 1.5
 >>> parse('ni!')
 'ni!'
-
-# end::PARSE_ATOM[]
-
-# tag::PARSE_LIST[]
 >>> parse('(gcd 18 45)')
 ['gcd', 18, 45]
 >>> parse('''
@@ -21,15 +17,15 @@
 ... ''')
 ['define', 'double', ['lambda', ['n'], ['*', 'n', 2]]]
 
-# end::PARSE_LIST[]
+# end::PARSE[]
 
 Doctest for `Environment`
 -------------------------
 
 # tag::ENVIRONMENT[]
 >>> from lis import Environment
->>> outer_env = {'a': 0, 'b': 1}
 >>> inner_env = {'a': 2}
+>>> outer_env = {'a': 0, 'b': 1}
 >>> env = Environment(inner_env, outer_env)
 >>> env['a'] = 111  # <1>
 >>> env['c'] = 222
@@ -64,11 +60,11 @@
 
 
 # tag::EVAL_QUOTE[]
->>> evaluate(parse('(quote no-such-name)'), {})
+>>> evaluate(parse('(quote no-such-name)'), standard_env())
 'no-such-name'
->>> evaluate(parse('(quote (99 bottles of beer))'), {})
+>>> evaluate(parse('(quote (99 bottles of beer))'), standard_env())
 [99, 'bottles', 'of', 'beer']
->>> evaluate(parse('(quote (/ 10 0))'), {})
+>>> evaluate(parse('(quote (/ 10 0))'), standard_env())
 ['/', 10, 0]
 
 # end::EVAL_QUOTE[]
@@ -156,11 +152,12 @@ def test_factorial():
     (if (= n 0)
         m
         (gcd n (mod m n))))
-(gcd 18 45)
+(display (gcd 18 45))
 """
-def test_gcd():
-    got = run(gcd_src)
-    assert got == 9
+def test_gcd(capsys):
+    run(gcd_src)
+    captured = capsys.readouterr()
+    assert captured.out == '9\n'
 
 
 quicksort_src = """
@@ -216,7 +213,7 @@ def test_newton():
 (define inc (make-adder 1))
 (inc 99)
 """
-def test_newton():
+def test_closure():
     got = run(closure_src)
     assert got == 100
 
@@ -228,13 +225,15 @@ def test_newton():
         n)
 )
 (define counter (make-counter))
-(counter)
-(counter)
-(counter)
+(display (counter))
+(display (counter))
+(display (counter))
 """
-def test_closure_with_change():
-    got = run(closure_with_change_src)
-    assert got == 3
+def test_closure_with_change(capsys):
+    run(closure_with_change_src)
+    captured = capsys.readouterr()
+    assert captured.out == '1\n2\n3\n'
+
 
 
 # tag::RUN_AVERAGER[]
@@ -256,4 +255,4 @@ def test_closure_with_change():
 def test_closure_averager():
     got = run(closure_averager_src)
     assert got == 12.0
-# end::RUN_AVERAGER[]
+# end::RUN_AVERAGER[]

18-with-match/lispy/py3.10/lis.py

@@ -58,10 +58,11 @@ def parse_atom(token: str) -> Atom:
         except ValueError:
             return Symbol(token)
 
+
 ################ Global Environment
 
 # tag::ENV_CLASS[]
-class Environment(ChainMap):
+class Environment(ChainMap[Symbol, Any]):
     "A ChainMap that allows changing an item in-place."
 
     def change(self, key: Symbol, value: object) -> None:
@@ -119,11 +120,11 @@ def standard_env() -> Environment:
 ################ Interaction: A REPL
 
 # tag::REPL[]
-def repl() -> NoReturn:
+def repl(prompt: str = 'lis.py> ') -> NoReturn:
     "A prompt-read-eval-print loop."
     global_env = standard_env()
     while True:
-        ast = parse(input('lis.py> '))
+        ast = parse(input(prompt))
         val = evaluate(ast, global_env)
         if val is not None:
             print(lispstr(val))
@@ -140,7 +141,10 @@ def lispstr(exp: object) -> str:
 ################ Evaluator
 
 # tag::EVALUATE[]
-KEYWORDS = ['quote', 'if', 'lambda', 'define', 'set!']
+KEYWORDS = {'quote', 'if', 'lambda', 'define', 'set!'}
+
+def is_keyword(s: Any) -> bool:
+    return isinstance(s, Symbol) and s in KEYWORDS
 
 def evaluate(exp: Expression, env: Environment) -> Any:
     "Evaluate an expression in an environment."
@@ -149,8 +153,6 @@ def evaluate(exp: Expression, env: Environment) -> Any:
             return x
         case Symbol(var):
             return env[var]
-        case []:
-            return []
         case ['quote', x]:
             return x
         case ['if', test, consequence, alternative]:
@@ -166,8 +168,8 @@ def evaluate(exp: Expression, env: Environment) -> Any:
             env[name] = Procedure(parms, body, env)
         case ['set!', Symbol(var), value_exp]:
             env.change(var, evaluate(value_exp, env))
-        case [op, *args] if op not in KEYWORDS:
-            proc = evaluate(op, env)
+        case [func_exp, *args] if not is_keyword(func_exp):
+            proc = evaluate(func_exp, env)
             values = [evaluate(arg, env) for arg in args]
             return proc(*values)
         case _:

18-with-match/lispy/py3.10/lis_test.py

@@ -73,10 +73,10 @@ def test_evaluate(source: str, expected: Optional[Expression]) -> None:
 def std_env() -> Environment:
     return standard_env()
 
-# tests for each of the cases in evaluate
+# tests for cases in evaluate
 
 def test_evaluate_variable() -> None:
-    env: Environment = dict(x=10)
+    env = Environment({'x': 10})
     source = 'x'
     expected = 10
     got = evaluate(parse(source), env)
@@ -168,8 +168,6 @@ def test_invocation_user_procedure(std_env: Environment) -> None:
     assert got == 22
 
 
-###################################### for py3.10/lis.py only
-
 def test_define_function(std_env: Environment) -> None:
     source = '(define (max a b) (if (>= a b) a b))'
     got = evaluate(parse(source), std_env)